TR2002 Transmitter Receiver

This ex-RAF equipment first appeared
on the government surplus market in the UK during the 1960s and
was suitable for conversion for use on the 2 metre amateur band.

I recall buying one but I don't think
I did much with it as it needed a pair of matched crystals to
make it a self-contained transmitter and receiver, but I think
I did get it going in transmit mode in conjunction with my normal
2-meter receiver.

I remember being very disappointed back
in 1963 as my purchase was missing some of its valves, although
I must admit that my memories are now pretty hazy. I do however
remember the frequency on which it operated. This was 121.5 MHz;
the international distress frequency for aircraft. Until recently
the merest sniff of a signal radiated from a house on 121.5MHz
would have been picked up by satellites and a helicopter might
have landed unannounced in your back garden. I believe this channel
was no longer monitored by satellite after 2009, but that is
not to say that it would not be picked up at your local airport.
I once tested a marine transmitter in our lab at Plessey using
decent shielded RF equipment and was surprised to hear the local
coastguard ask me to desist transmissions. I was tweaking the
output on the marine distress calling channel, so powering the
TR2002 in an unmodified state even with a dummy load is certainly
not recommended.

In my junk box after nearly 50 years
I still have the microphone transformer and the transmit crystal
from my original purchase...

Here are some general views of my latest
TR2002..

You can see that the set is constructed
on two separate chassis; the upper being the receiver which is
marked "Type 127; 10P/13202" and the lower the transmitter
and modulator including a small dynamotor which supplies the
HT. The lower chassis is marked "Type 96; 10R/176".

The TR2002 was designed for use on a
24V supply and connections are relatively simple and straightforward
being aerial, headphones, microphone and a send/receive switch.

It's RAF code is 10D/17997 and the manufacturer,
clearly seen on the front panel label, was Burndept of Erith
Kent

Brief technical details, including valve
line-up are as follows:

Receiver: Fixed frequency of 121.5MHz
using a 13.972MHz crystal and an IF of 9.72MHz

The microphone amplifier uses a pair
of push pull amplifier valves 1V1 & 1V2: CV2135 (6BR7), fed
by a microphone transformer and the output a pair of push pull
valves 1V3 & 1V4: CV416 (6F17) driving a modulation transformer
in the HT supply of the RF output valve. This of course gives
a high-level AM transmission.

My first purchase had been disappointing
as the 6F17 valves had been removed. This type was a special
beam tetrode as scarce as hens teeth in Liverpool. Whether the
Air Ministry had ordered the valves to be removed before disposal,
or whether it was the proprietor of Super Radio I don't know?
Maybe the first few that had been sold had been fired up and
upset the staff at Liverpool Airport who'd complained to Mr Benson,
I can't say, but I wouldn't be surprised...

This latest acquisition is perfect.
All the valves are present and it's unmodified and completely
original... most unusual.